Sioc ceramic material for preparing lithium-ion battery negative pole, preparation method thereof and lithium-ion battery

Abstract

The invention discloses a SiOC ceramic material used for preparing the cathode of a lithium ion battery, a preparation method thereof and a lithium ion battery prepared from the ceramic material. The SiOC ceramic material comprises silicon, oxygen and carbon, and the mol ratio of silicon to oxygen to carbon is 1: alpha: beta, wherein, alpha is 0.4 to 0.2, beta is 0.4 to 5.0, and alpha plus beta is 0.8 to 7.0. The preparation method comprises the following steps: preparing organosilicon polymers with a molecular formula of a(R1R2SiO)x(R3R4SiO2)y(R5R6SiO3)zb, wherein, a and b are terminated functional groups, R1, R2, R3, R4, R5 and R6 are functional groups, at least one of which is hydrogen groups or alkenyl groups, x is 0.3 to 1, y is 0 to 0.7, z is 0 to 0.5, and x plus y plus z is 1; preparing organic small molecular compounds which comprise active groups that can react with hydrogen groups, silanol groups or alkenyl groups; mixing the organosilicon polymers with the organic small molecular compounds, preparing the two into a copolymer through crossing and curing, and carrying out pyrolysis so as to obtain the SiOC ceramic material. The lithium ion battery provided in the invention has the characteristics of high capacity, good cycle performance and high reversible capacity.

Description

Technical field [0001] The invention involves the field of composite materials and battery fields, and especially involves a SiOC ceramic material and preparation method for preparing lithium -ion batteries. Background technique [0002] Compared with traditional secondary batteries, lithium -ion batteries have the advantages of high opening voltage, high energy density, long service life, no memory effect, pollution -free and self -spontaneous power, so their applications are becoming wider and wider.The current commercial lithium -ion battery negative material is carbon negative material, and its theoretical capacity is only 372mAh / g, and it has been developed close to the theoretical value.Wide demand for chemical power supply.Therefore, it is imperative to find a new type of negative material system that can replace carbon materials. [0003] Silicon is one of the ideal negative candidate materials, which has the following advantages: [0004] (1) The highest capacity density...

AI Technical Summary

Problems solved by technology

[0009] First, the serious volume effect of silicon during the charge-discharge cycle leads to the collapse of the material structure;

[0010] Secondly, the irreversible transformation of silicon from crystalline state to disordered state during the process of intercalation and delithiation of lithium causes serious damage to the structure of the material;

[0011] Third, silicon has poor electrical conductivity, and the uneven reaction with lithium reduces the cycle performance of silicon materials

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